Stackable semiconductor device assemblies

ABSTRACT

A semiconductor device assembly includes a substrate and a semiconductor die adjacent to a first surface of the substrate. The substrate also includes a second surface opposite from the first surface, an opening extending from the first surface and the second surface, contact pads on the first surface, and substrate pads on the second surface, adjacent to the opening. Bond pads of the semiconductor die are aligned with the opening through the substrate. Intermediate conductive elements, such as bond wires, extend from bond pads of the semiconductor die, through the opening, to substrate pads on the opposite, second surface of the substrate. An encapsulant, which fills the opening and covers the intermediate conductive elements, protrudes beyond a plane in which the second surface of the substrate is located. Another electronic device, such as another semiconductor device package, may communicate electrically with the die of the semiconductor device assembly through the contact pads on the first surface of the substrate. In some embodiments, the other electronic device may be stacked with the semiconductor device assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/866,065, filed Oct. 2, 2007, which is a continuation of U.S. patentapplication Ser. No. 11/437,550, filed May 19, 2006, now U.S. Pat. No.7,381,591, issued Jun. 3, 2008, which is a continuation of U.S. patentapplication Ser. No. 11/070,364, filed Mar. 1, 2005, now U.S. Pat. No.7,329,945, issued Feb. 12, 2008, which is a continuation of U.S. patentapplication Ser. No. 09/699,537, filed Oct. 30, 2000, now U.S. Pat. No.6,861,290, issued Mar. 1, 2005, which is a divisional of U.S. patentapplication Ser. No. 09/483,483, filed Jan. 14, 2000, now U.S. Pat. No.6,265,766, issued Jul. 24, 2001, which is a continuation of U.S. patentapplication Ser. No. 08/948,936, filed Oct. 10, 1997, now U.S. Pat. No.6,201,304, issued Mar. 13, 2001, which is a continuation of U.S. patentapplication Ser. No. 08/574,662, filed Dec. 19, 1995, now U.S. Pat. No.5,719,440, issued Feb. 17, 1998. The disclosure of each of thepreviously referenced U.S. patent applications and patents is herebyincorporated herein by this reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for connecting a baresemiconductor die having a size and bond pad arrangement, either solderball arrangement, or pin arrangement (hereinafter referred to generallyas a “terminal arrangement”), which does not conform to a printedcircuit board with a specific or standardized pin out, connector pad, orlead placement (hereinafter referred to generally as a “connectionarrangement”). More particularly, the present invention relates to anintermediate conductor-carrying substrate (hereinafter referred togenerally as an “adaptor board”) for connecting a non-conforming baredie to another printed circuit board having a given connectionarrangement (hereinafter referred to generally as a “master board”).

2. State of the Art

Definitions: The following terms and acronyms will be used throughoutthe application and are defined as follows:

BGA—Ball Grid Array: An array of minute solder balls disposed on anattachment surface of a semiconductor die wherein the solder balls arerefluxed for simultaneous attachment and electrical communication of thesemiconductor die to a printed circuit board.

COB—Chip On Board: The techniques used to attach semiconductor dice to aprinted circuit board, including flip-chip attachment, wire bonding, andtape automated bonding (“TAB”).

Flip-Chip: A chip or die that has bumped terminations spaced around theactive surface of the die and is intended for facedown mounting.

Flip-Chip Attachment: A method of attaching a semiconductor die to asubstrate in which the die is flipped so that the connecting conductorpads on the face of the die are set on mirror-image pads on thesubstrate (i.e., printed circuit board) and bonded by refluxing thesolder.

Glob Top: A glob of encapsulant material (usually epoxy or silicone or acombination thereof) surrounding a semiconductor die in the COB assemblyprocess.

PGA—Pin Grid Array: An array of small pins extending substantiallyperpendicularly from the major plane of a semiconductor die, wherein thepins conform to a specific arrangement on a printed circuit board forattachment thereto.

SLICC—Slightly Larger than Integrated Circuit Carrier: An array ofminute solder balls disposed on an attachment surface of a semiconductordie similar to a BGA, but having a smaller solder ball pitch anddiameter than a BGA.

State-of-the-art COB technology generally consists of threesemiconductor die to printed circuit board attachment techniques:flip-chip attachment, wire bonding, and TAB.

Flip-chip attachment consists of attaching a semiconductor die,generally having a BGA, a SLICC or a PGA, to a printed circuit board.With the BGA or SLICC, the solder ball arrangement on the semiconductordie must be a mirror-image of the connecting bond pads on the printedcircuit board such that precise connection is made. The semiconductordie is bonded to the printed circuit board by refluxing the solderballs. With the PGA, the pin arrangement of the semiconductor die mustbe a mirror-image of the pin recesses on the printed circuit board.After insertion, the semiconductor die is generally bonded by solderingthe pins into place. An under-fill encapsulant is generally disposedbetween the semiconductor die and the printed circuit board to preventcontamination. A variation of the pin-in-recess PGA is a J-lead PGA,wherein the loops of the Js are soldered to pads on the surface of thecircuit board. Nonetheless, the lead and pad locations must coincide, aswith the other referenced flip-chip techniques.

Wire bonding and TAB attachment generally begins with attaching asemiconductor die to the surface of a printed circuit board with anappropriate adhesive. In wire bonding, a plurality of bond wires areattached, one at a time, from each bond pad on the semiconductor die andto a corresponding lead on the printed circuit board. The bond wires aregenerally attached through one of three industry-standard wire bondingtechniques: ultrasonic bonding, using a combination of pressure andultrasonic vibration bursts to form a metallurgical cold weld;thermocompression bonding, using a combination of pressure and elevatedtemperature to form a weld; and thermosonic bonding, using a combinationof pressure, elevated temperature, and ultrasonic vibration bursts. Thedie may be oriented either face up or face down (with its active surfaceand bond pads either up or down with respect to the circuit board) forwire bonding, although face up orientation is more common. With TAB,metal tape leads are attached between the bond pads on the semiconductordie and the leads on the printed circuit board. An encapsulant isgenerally used to cover the bond wires and metal tape leads to preventcontamination.

Although the foregoing methods are effective for bonding semiconductordice to printed circuit boards, the terminal arrangements of the diceand the connection arrangements of the boards must be designed toaccommodate one another. Thus, it may be impossible to electricallyconnect a particular semiconductor die to a printed circuit board forwhich the semiconductor die terminal arrangement was not designed tomatch the board's connection arrangement. With either wire bond or TABattachment, the semiconductor die bond pad may not correspond to thelead ends on the circuit board, and thus attachment is either impossibleor extremely difficult due to the need for overlong wires and thepotential for inter-wire contact and shorting. With flip-chipattachment, if the printed circuit board connection arrangement is not amirror-image of the solder ball or pin arrangement (terminalarrangement) on the semiconductor die, electrically connecting theflip-chip to the printed circuit board is impossible.

Therefore, it would be advantageous to develop an apparatus forconnecting a semiconductor die having a size and bond pad arrangement,solder ball arrangement, or pin arrangement (“I/O pattern”) which doesnot conform to a printed circuit board with a specific or standardizedpin out, connection pad location, or lead placement (“I/O pattern”).

SUMMARY OF THE INVENTION

The present invention relates to an intermediate printed circuit boardor other conductor-carrying substrate that functions as an adaptor boardfor electrically connecting one or more bare semiconductor dice of avariety of sizes and bond pad locations, solder ball arrangement, or pinarrangement, to a master printed circuit board with a specific orstandardized pin out, connector pad location, or lead placement.

An adaptor printed circuit board or substrate (“adaptor board”) is sizedand configured with an I/O pattern to accommodate its attachment to themaster printed circuit board (“master board”). If the master board isconfigured to receive a specific pin out or specific connector padlocations, the adaptor board is configured on its master boardattachment surface with pins or solder balls in mirror-image to themaster board connection arrangement to make electrical contact with thespecific pin out or connector pads on the printed circuit board. If themaster board is configured to receive a bond wire, the adaptor board isconfigured and sized to provide wire bond pads on its upper surfaceclosely adjacent the bond pads of the master board leads. The adaptorboard can, of course, be configured to accommodate other attachment andelectrical connection means known in the industry, as well as othercomponents in addition to the semiconductor die or dice carried thereon.

On the semiconductor die side of the adaptor board, one or moresemiconductor dice are attached. If a “flip-chip” die is attached to theadaptor board, the adaptor board will, of course, be configured with anI/O pattern to receive the flip-chip with a specific pin out orconnector pad locations. The pin out or connector pads on the adaptorboard are connected to circuit traces on or through the adaptor board.The circuit traces form the electrical communication path from the pinrecesses or connector pads on the adaptor board to the connection pointsto the master board.

If a “leads over” die is used with the adaptor board, the bond pads onthe die are wire bonded to the adaptor board. Preferably, the leads overdie is attached to the adaptor board with the bond pads facing theadaptor board. The bond wires are attached to the leads over die bondpads and extend into a via or vias in the adaptor board. The bond wiresare attached to an I/O pattern of adaptor board bond pads within the viafrom which circuit traces extend, or to leads on the master board sideof the adaptor board.

It is, of course, understood that the leads over die can be attached tothe adaptor board with the bond pads facing away from the adaptor board.Thus, the bond wires are simply attached to the bond pads on the leadsover die and to a corresponding I/O pattern of adaptor board pad on thesemiconductor die side of the adaptor board.

Preferably, the exposed circuitry of the die and the die-to-adaptorboard interconnection is sealed from contamination by a glob top afterwire bonding or an underflow compound in the case of a flip-chipattachment.

Furthermore, it is understood that with the use of wire bonds, theadaptor boards can be stacked on top of each other and connected to theadaptor board as by wire bonding.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming that which is regarded as the present invention,the advantages of this invention can be more readily ascertained fromthe following description of the invention when read in conjunction withthe accompanying drawings in which:

FIG. 1 is a side view of one embodiment of the present invention;

FIG. 2 is a side view of a second embodiment of the present invention;

FIG. 2A is a top view of the second embodiment of the present inventionshown in FIG. 2;

FIG. 3 is a side view of a third embodiment of the present invention;

FIG. 3A is an upside-down exploded perspective view of selected portionsof the third embodiment; and

FIG. 4 is a side view of a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a first embodiment of the present inventiondesignated as a flip-chip style/flip-chip attachment assembly 100.Assembly 100 comprises a semiconductor die 12 having an inverted activesurface 14 with at least one flip-chip electric connection 16 (such as aC4 solder bump connection, a pin connection, or a surface mount J-leadconnection, by way of example) extending substantially perpendicularlyfrom a bond pad 15 on the semiconductor die active surface 14. Theflip-chip electric connections 16 are attached to an upper surface 20 ofan adaptor board 18 in such a manner that the flip-chip electricconnections 16 make electrical contact with electrical contact elements21 in or on the surface of adaptor board 18. The electrical contactelements 21 make electrical communication between each flip-chipelectric connection 16, through circuit traces 23 (exemplary tracesshown in broken lines) in the adaptor board 18, to at least one masterboard connector 22 extending substantially perpendicularly from a lowersurface 24 of the adaptor board 18 to connect adaptor board 18 to analigned terminal 31 on master board 30. Preferably, a sealing compound26 is disposed between the semiconductor die 12 and the adaptor board 18to prevent contamination of the flip-chip electric connections 16 and tomore firmly secure semiconductor die 12 to adaptor board 18.

In actual practice, there will be a plurality of terminals 31 arrangedin a specific, perhaps industry-standard pattern, on master board 30,and master board connectors 22 will be arranged in a mirror-imagepattern to terminals 31 for mating connection therewith. Master boardconnectors 22 and terminals 31 may comprise any electrical connectionmechanism known in the art, in addition to those previously describedherein.

FIGS. 2 and 2A illustrate a second embodiment of the present inventiondesignated as a flip-chip style/wire bond attachment assembly 200.Components common to both FIG. 1 and FIG. 2 retain the same numericdesignation. The assembly 200 comprises the semiconductor die 12 havingactive surface 14 with at least one flip-chip electric connection 16, asknown in the art, extending substantially perpendicularly from a bondpad 15 on the semiconductor die active surface 14. The flip-chipelectric connections 16 are attached to the adaptor board upper surface20 in such a manner that the flip-chip electric connections 16 makeelectrical contact with electrical contact elements 21 on the adaptorboard 18. The electrical contact elements 21 communicate between eachflip-chip electric connection 16 to bond pads 28 on the adaptor boardupper surface 20 through circuit traces 23. The adaptor board lowersurface 24 is bonded to an upper surface 36 of a master board 30 with anadhesive 32, which may comprise a liquid or gel adhesive, or an adhesivetape, all as known in the art. If desired, adhesive 32 may be aheat-conductive adhesive. A wire bond 34 extends from each adaptor boardbond pad 28 to a corresponding bond pad or lead end 35 on the uppersurface 36 of master board 30, bond pad or lead end 35 communicatingwith other components mounted to master board 30 or with othercomponents on other boards or other assemblies through circuit traces orother conductors known in the art.

FIGS. 3 and 3A illustrate a third embodiment of the present inventiondesignated as a wire bond style/flip-chip attachment assembly 300.Components which are common to the previous figures retain the samenumeric designation. The assembly 300 comprises an invertedsemiconductor die 12 having active surface 14 with at least one bond pad38 on the semiconductor die active surface 14. As illustrated, the bondpads 38 are arranged in two rows extending down the longitudinal axis ofsemiconductor die 12 being located transverse to the plane of the page,such an arrangement commonly being used for a “leads over” connection toframe leads extending over the die in its normal, upright position. Thesemiconductor die active surface 14 is bonded to the adaptor board uppersurface 20 with an insulating, sealing adhesive 40. The adaptor board 18includes at least one or more wire bond vias 42 which is located in aposition or positions aligned with the semiconductor die bond pads 38.Each individual wire bond 134 is connected to each correspondingindividual semiconductor die bond pad 38. Each wire bond 134 extendsfrom the semiconductor die bond pad 38 to a corresponding bond pad orlead 39 on the adaptor board lower surface 24, which communicates withmaster board connectors 22 through circuit traces 23. The master boardterminals 31 are in electrical communication with at least one masterboard connector 22 extending substantially perpendicularly from theadaptor board lower surface 24. Preferably, a sealant 44 encases thebond wires 134 and seals the wire bond via 42 to prevent contaminationand damage to the wire bonds.

FIG. 4 illustrates a fourth embodiment of the present inventiondesignated as a wire bond style/wire bond attachment assembly 400.Components which are common to the previous figures retain the samenumeric designation. The assembly 400 comprises the semiconductor die 12having active surface 14 with at least one bond pad 38 on thesemiconductor die active surface 14. As with the embodiment of FIG. 3,semiconductor die 12 in this instance employs bond pads 38 in a “leadsover” configuration. The semiconductor die active surface 14 is bondedto the adaptor board upper surface 20 with an insulating, sealingadhesive 40. The adaptor board 18 includes at least one or more wirebond vias 42 which are located in a position or positions aligned withthe semiconductor die bond pads 38. Each individual wire bond 134 isconnected to each corresponding semiconductor die bond pad 38. Each wirebond 134 extends from the semiconductor die bond pad 38 to acorresponding bond pad 46 within the wire bond via 42. The via bond pads46 are in electrical communication through circuit traces 23 with atleast one corresponding adaptor board bond pad 28. The adaptor boardlower surface 24 is bonded to the master board upper surface 36 with theadhesive 32. Wire bonds 34 extend from the adapter board upper surface20 to a corresponding bond pad or lead end 35 on the master board uppersurface 36. Preferably, the wire bond via sealant 44 encases the bondwires 134 and seals the wire bond via 42 to prevent contamination.

Having thus described in detail preferred embodiments of the presentinvention, it is to be understood that the invention defined by theappended claims is not to be limited by particular details set forth inthe above description as many apparent variations thereof are possiblewithout departing from the spirit or scope thereof.

1. An apparatus, comprising: a substrate including a planar firstsurface, a second surface opposite from the first surface, an elongateopening extending from the first surface to the second surface andincluding an elongate first side and an elongate second side, substratepads at the second surface, adjacent to the first and second elongatedsides of the elongated opening, contact pads at the first surface, andconductive traces establishing electrical communication between thecontact pads and the substrate pads; a semiconductor die on the firstsurface of the substrate, the semiconductor die including an activesurface and die pads at the active surface; bond wires extending fromthe die pads, through the opening, and to first and second rows ofsubstrate pads; and encapsulant covering the bond wires and protruding afirst profile distance beyond a plane in which the second surface of thesubstrate is located.
 2. The apparatus of claim 1, wherein the activesurface of the semiconductor die faces the die attach surface of thesubstrate.
 3. The apparatus of claim 1, further comprising: adhesivesecuring the semiconductor die to the substrate.
 4. The apparatus ofclaim 3, wherein the adhesive extends laterally beyond an outerperiphery of the semiconductor die.
 5. The apparatus of claim 3, whereinthe adhesive does not extend laterally beyond an inner periphery of thesubstrate that defines the elongate opening.
 6. The apparatus of claim3, wherein the adhesive comprises an adhesive-coated tape or anadhesive-coated film.
 7. The apparatus of claim 1, wherein thesemiconductor die includes a first row of die pads and a second row ofdie pads.
 8. The apparatus of claim 7, wherein: first bond wiresestablish electrical communication between first die pads of the firstrow of die pads and corresponding first substrate pads of the first rowof substrate pads; and second bond wires establish electricalcommunication between second die pads of the second row of die pads andcorresponding second substrate pads of the second row of substrate pads.9. The apparatus of claim 1, further comprising: a semiconductor devicepackage stacked on the substrate.
 10. The apparatus of claim 9, whereinthe semiconductor device package is stacked over the first surface ofthe substrate.
 11. The apparatus of claim 10, wherein the semiconductordevice package communicates electrically with the semiconductor diethrough the contact pads at the first surface of the substrate.
 12. Theapparatus of claim 10, wherein an area of the second surface of thesubstrate that is superimposed by the semiconductor die on the firstsurface of the substrate lacks contact pads.
 13. The apparatus of claim1, further comprising: a printed circuit board including: a surface overwhich the substrate is positioned; terminals exposed at the surface; andconductive traces extending from the terminals; bond wires establishingelectrical communication between the terminals of the printed circuitboard and corresponding contact pads of the substrate; and at leastanother electrical component in electrical communication with theterminals of the printed circuit board through the conductive traces ofthe printed circuit board.
 14. A semiconductor device assembly,comprising: a substrate including: a planar first surface; a secondsurface opposite from the first surface; an opening extending from thefirst surface to the second surface and at a substantially centrallocation of the substrate; substrate pads located on the second surface,adjacent to the opening; and contact pads located on the first surface;a semiconductor die adjacent to the first surface of the substrate, thesemiconductor die including bond pads aligned with the opening;intermediate conductive elements extending from the bond pads of thesemiconductor die to corresponding substrate pads on the second surfaceof the substrate; an encapsulant filling the opening and covering theintermediate conductive elements and the corresponding substrate pads ofthe substrate, the encapsulant protruding beyond a plane in which thesecond surface of the substrate is located.
 15. The semiconductor deviceassembly of claim 14, wherein the intermediate conductive elementscomprise bond wires.
 16. The semiconductor device assembly of claim 14,wherein the opening comprises an elongate opening.
 17. The semiconductordevice assembly of claim 14, further comprising: adhesive securing thesemiconductor die to the substrate.
 18. The semiconductor deviceassembly of claim 17, wherein the adhesive extends laterally beyond anouter periphery of the semiconductor die.
 19. The semiconductor deviceassembly of claim 17, wherein the adhesive does not extend laterallybeyond an inner periphery of the substrate that defines the opening. 20.The semiconductor device assembly of claim 17, wherein the adhesivecomprises an adhesive-coated tape or an adhesive-coated film.
 21. Thesemiconductor device assembly of claim 14, wherein the substrate pads ofthe substrate include a first row of substrate pads adjacent to a firstside of the opening and a second row of substrate pads adjacent to asecond side of the opening.
 22. The semiconductor device assembly ofclaim 21, wherein the semiconductor die includes a first row of die padsand a second row of die pads.
 23. The apparatus of claim 22, wherein:first intermediate conductive elements establish electricalcommunication between first die pads of the first row of die pads andcorresponding first substrate pads of the first row of substrate pads;and second intermediate conductive elements establish electricalcommunication between second die pads of the second row of die pads andcorresponding second substrate pads of the second row of substrate pads.24. An apparatus, comprising: a printed circuit board including asurface, terminals exposed at the surface, and circuit traces associatedwith the terminals; a first package on the surface of the printedcircuit board, the first package including: a substrate including: aplanar first surface; a second surface opposite from the first surface;an elongate opening extending from the first surface to the secondsurface and including an elongate first side and an elongate secondside; substrate pads at the second surface, adjacent to the first andsecond elongated sides of the elongated opening; contact pads at thefirst surface; and conductive traces establishing electricalcommunication between the contact pads and the substrate pads; anadhesive on a first surface of the substrate; a semiconductor diesecured to the first surface of the substrate with the adhesive, thesemiconductor die including an active surface and die pads at the activesurface; first bond wires extending from the die pads, through theopening, and to first and second rows of substrate pads; and encapsulantcovering the bond wires and protruding a first profile distance beyond aplane in which the second surface of the substrate is located; and asecond package stacked on the first package.
 25. The apparatus of claim24, wherein the second package is identical to the first package. 26.The apparatus of claim 25, wherein the second package communicateselectrically with the first package through contact pads on the firstsurface of the substrate of the first package.
 27. The apparatus ofclaim 24, wherein an area on the second surface of the substrate of thefirst package with which the semiconductor die on the first surface ofthe substrate is superimposed lacks contact pads.
 28. The apparatus ofclaim 24, wherein the active surface of the semiconductor die of thefirst package faces the die attach surface of the substrate of the firstpackage.
 29. The apparatus of claim 24, wherein the first packagefurther includes: adhesive securing the semiconductor die to thesubstrate.
 30. The apparatus of claim 29, wherein the adhesive extendslaterally beyond an outer periphery of the semiconductor die.
 31. Theapparatus of claim 29, wherein the adhesive does not extend laterallybeyond an inner periphery of the substrate that defines the elongateopening.
 32. The apparatus of claim 29, wherein the adhesive comprisesan adhesive-coated tape or an adhesive-coated film.
 33. The apparatus ofclaim 24, wherein the semiconductor die of the first package includes afirst row of die pads and a second row of die pads.
 34. The apparatus ofclaim 33, wherein: first bond wires establish electrical communicationbetween first die pads of the first row of die pads and correspondingfirst substrate pads of the first row of substrate pads; and second bondwires establish electrical communication between second die pads of thesecond row of die pads and corresponding second substrate pads of thesecond row of substrate pads.
 35. The apparatus of claim 24, furthercomprising: bond wires establishing electrical communication between theterminals of the printed circuit board and corresponding contact pads ofthe substrate; and at least another electrical component in electricalcommunication with the terminals of the printed circuit board throughthe conductive traces of the printed circuit board.